Which scenario most effectively demonstrates the combined use of Diffie‑Hellman and HMAC to secure communications?单项选择题

Employing Diffie‑Hellman for encryption and using asymmetric digital signatures solely for message authentication.

Relying on a fixed symmetric key for all transmissions while periodically using Diffie‑Hellman to verify message integrity

Using Diffie‑Hellman to establish a shared secret, then applying HMAC to each transmitted message with that key to ensure integrity and authenticity.

Directly encrypting messages with a Diffie‑Hellman derived key without additional authentication measures